1. Field of the Invention
The present invention relates to a color electrophotographic image forming apparatus.
2. Description of the Related Art
There is known a developing device of a rotary type in a color electrophotographic image forming apparatus. In the developing device of the rotary type, a plurality of developing cartridges each containing developer of a different color from each other are supported around a rotary member. Then, a rotative force from a motor is transmitted to the rotary member through a rotative force transmitting means. With this structure, the rotary member is allowed to rotatably move. In the developing device of the rotary type, one of the developing cartridges is moved to a developing position in which the developing cartridge is opposed to a photosensitive drum. Then, an electrostatic latent image formed on the photosensitive drum is developed with use of the developer by the developing cartridge. Further, this operation is performed on the plurality of developing cartridges, whereby a color image is formed on a recording medium.
In the image forming apparatus adopting the developing device of the rotary type, a color image may be formed with use of a small photosensitive drum. Thus, an apparatus main body is advantageously downsized.
Then, a user detachably mounts the developing cartridges to the rotary member. With this structure, the operability in a case of maintenance may be improved.
In this case, there is known a structure in which the developing cartridges are moved by hand to the replacement position provided in the apparatus main body. Specifically, with rotation of a knob by hand, the developing cartridge switching mechanism may be rotated. As a result, the developing cartridge may be positioned to the replacement port by hand (refer to Japanese Patent Application Laid-Open No. H06-250485). With this structure, the operability in replacing the developing cartridge may be improved.
However, in the above-mentioned conventional example, it is conceived that the knob becomes a rotation load when the developing cartridge switching mechanism is rotated by the motor.